CD8+ T‐cells are potentially protective against SARS‐2 infections, as they have been protective against previous SARS‐CoV infections.[64, 129] In severe COVID‐19 illness, peripheral circulating CD8+ T‐cell counts are low (Figure S1B, Supporting Information);[127] in general, the severity of illness is inversely correlated with CD8+ T‐cell counts. Here, CD8A is linked to COVID-19.